云南地区构造应力应变场年变化特征的数值模拟
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摘要
根据云南地区的地质构造、三维波速结构、地震活动性等相关资料,建立云南地区三维非线性有限元模型,模拟云南地区构造应力应变场的年变化特征。结果表明:1)云南地区的地壳运动速度具有北强南弱、西高东低、围绕东喜马拉雅构造结顺时针旋转的特征;2)由于印度洋板块的俯冲作用,造成云南地区地壳运动速度场的规律性变化:红河断裂带以东由北部的SEE向到南部的SE向,而以西为SE-NS-SW向变化;3)最大主应变具有西高东低,北强南弱的特征,达到10-8量级,主要分布在滇西地区、安宁河断裂带两侧及小江断裂北段;4)最大主应力主要分布在断裂带沿线及其交汇处,最大差应力分布与其较为一致;滇南地区具有较大的差应力分布,且处于拉张状态,而其他地区大部分为压性状态。
On the basis of the geological structure,3D velocity structure and seismic activity in the Yunnan area a 3D finite element model is established.for simulating the present-day annual change characteristics of tectonic stress-strain fields in Yunnan area.The results indicate that: 1) The crustal movements in the north and west of the area are stronger than that in the south and east,also the Yunnan area is characterized by clockwise rotation around the eastern Himalayan syntaxis.2) Because of the subduction of the India plate,the directions of the crustal movement are as follows: in the east of Red river fault,it's from SEE in the north to SE in the south,while in the west it's SE-NS-SW.3)The maximum principal strain shows the pattern of higher value in the west and north but lower in the east and south,also the maximum value reaches 10-8,it's mainly on the western Yunnan area,both sides of the Anning river fault and the north segment of Xiaojiang fault.4)The maximum principal stress are mostly located along the faults zones and their intersections,the distribution of the maximum differential stress accords with it.In addition,in the south of Yunnan area the differential stress is high,and is tensile,while that is mostly compressive in the other place.
On the basis of the geological structure,3D velocity structure and seismic activity in the Yunnan area a 3D finite element model is established.for simulating the present-day annual change characteristics of tectonic stress-strain fields in Yunnan area.The results indicate that: 1) The crustal movements in the north and west of the area are stronger than that in the south and east,also the Yunnan area is characterized by clockwise rotation around the eastern Himalayan syntaxis.2) Because of the subduction of the India plate,the directions of the crustal movement are as follows: in the east of Red river fault,it's from SEE in the north to SE in the south,while in the west it's SE-NS-SW.3)The maximum principal strain shows the pattern of higher value in the west and north but lower in the east and south,also the maximum value reaches 10-8,it's mainly on the western Yunnan area,both sides of the Anning river fault and the north segment of Xiaojiang fault.4)The maximum principal stress are mostly located along the faults zones and their intersections,the distribution of the maximum differential stress accords with it.In addition,in the south of Yunnan area the differential stress is high,and is tensile,while that is mostly compressive in the other place.
引文
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2成尔林.四川及其邻区现代构造应力场和现代构造运动特征[J].地震学报,1981,3(3):231-241.
3谢富仁,等.中国西南地区现代构造应力场基本特征[J].地震学报,1993,15(4):407-417.
4王琪,等.中国大陆现今构造变形GPS观测数据与速度场[J].地学前缘,2002,9(2):415-429.
5杨国华,等.云南地区现今地壳水平运动与变形特征[J].大地测量与地球动力学,2003,23(2):7-14.
6张希,等.川滇地区地壳水平运动特征与强震关系研究[J].大地测量与地球动力学,2003,23(3):35-41.
7申重阳,等.云南地区主要断层运动模型的GPS数据反演[J].大地测量与地球动力学,2002,22(3):46-51.
8王椿镛,等.川滇地区地壳上地幔三维速度结构研究[J].地震学报,2002,24(1):1-6.
9江在森,等.GPS初步结果揭示的中国陆地水平应变场与构造变形[J].地球物理学报,2003,46(3):352-358.
10唐荣昌,韩渭滨.四川活动断裂与地震[M].北京:地震出版社,1989.
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